|
|
Human neurons are so small that they require a microscope in order to be seen. However, some neurons can be up to 3 feet long, such as those that extend from the spinal cord to the toes.
More than 150,000 Americans killed by cardiovascular disease are younger than the age of 65 years.
According to the National Institute of Environmental Health Sciences, lung disease is the third leading killer in the United States, responsible for one in seven deaths. It is the leading cause of death among infants under the age of one year.
When Gabriel Fahrenheit invented the first mercury thermometer, he called "zero degrees" the lowest temperature he was able to attain with a mixture of ice and salt. For the upper point of his scale, he used 96°, which he measured as normal human body temperature (we know it to be 98.6° today because of more accurate thermometers).
On average, someone in the United States has a stroke about every 40 seconds. This is about 795,000 people per year.
![Lake position in the landscape and proportion of water received as groundwater (data from Webster et](https://biology-forums.com/gallery/47/medium_33_19_02_12_5_42_32_20651521.jpeg)
![The recent mass upheavals in Tunisia, Egypt, Libya, Yemen, and Syria gave political scientists a cha](https://biology-forums.com/gallery/47/medium_262797_12_08_15_1_33_47_221751025.png)